1. Field of the Invention
The present invention relates generally to the field of photographic and/or video image capture systems and, more particularly, to an improved image capture system capable of combining the individual images from at least two image capture devices to produce a virtual camera for simulated line-of-sight image capture.
2. Description of the Related Art
A fundamental challenge in photographic and/or video image capture is ensuring that the image capture device and subject are properly stationed to provide line-of-sight image capture. As used herein, the term "line-of-sight image capture" means capturing a photographic and/or video image while the subject is looking directly into the lens of the image capture device. Line-of-sight image capture is desirable in that the resulting photographic and/or video images show the subject looking outward toward a viewer for simulated face-to-face contact. If line-of-sight image capture is not performed, the subject has the appearance of staring off away from the viewer which, as will be appreciated, diminishes the intimacy associated with face-to-face contact.
Line-of-sight image capture involves two basic operations. First, the image capture device and the subject must be positioned such that the subject is disposed within the field of view of the image capture device. This may be accomplished by adjusting the position of the subject and/or image capture device while monitoring the position of the subject through the use of a viewfinder or preview window. Second, the subject must look directly into the lens of the image capture device during image capture. The end result is a photographic and/or video image which depicts the subject looking directly outward for simulated face-to-face contact with a viewer.
Line-of-sight image capture is not particularly difficult when endeavoring to capture the photographic and/or video image of another person. An operator can simply view the subject within the viewfinder, adjust the image capture device and/or the positioning of the subject to ensure that the subject is within the viewing angle of the lens, and then instruct the subject to look into the lens before activating the image capture device. Unique challenges exist, however, when the operator of the image capture device is desirous of capturing his or her own photographic and/or video image. For example, in the photographic context, it may be difficult for the operator to ensure that they are properly disposed within the viewing angle of the image capture device. The operator may attempt to take his or her own photographic image by holding a photographic image capture device at arms length and pointing it back at himself or herself. This may be problematic, however, in that the operator is incapable of previewing their own image because the viewfinder is located on the opposite side of the photographic image capture device.
This problem has been overcome in the video camcorder context with the advent of viewfinders that may be selectively positioned in the same direction as the lens to allow operators to view themselves while capturing their own video image. Notwithstanding this improvement, line-of-sight image capture is nonetheless difficult to perform because the operator must, by definition, look away from the lens of the image capture device in order to preview their image in the viewfinder. If the operator performs image capture while looking at the viewfinder, they will appear to be staring off away from a viewer. If the operator looks back to the lens prior to performing image capture, they run the risk of inadvertently moving the position of the lens such that the resulting images are not centered within the field of view.
Computer-based image capture systems suffer similar drawbacks in performing line-of-sight image capture. Computer-based image capture systems may include, for example, video conferencing systems, video telephony systems, video messaging systems, video postcard systems, multimedia training systems, and multimedia authoring systems. At a minimum, such systems include a display for visually communicating graphical and/or textual information to an operator, an image capture device for capturing the photographic and/or video image of the operator, and a computer processing unit for coordinating the operation of the overall system. The image capture device is disposed at a predetermined location about the periphery of the display such that the operator has an unobstructed view of the display.
The main obstacle in performing line-of-sight image capture in such computer-based image capture systems stems from the physical distance or offset between the image capture device and the display. More specifically, line-of-sight image capture in computer-based image capture systems can only be conducted at the expense of viewing the information on the display. This may be seen, for example, with reference to the prior art desktop video conferencing station 2 shown in FIG. 1. The video conferencing station 2 comprises a video display 4, an image capture device 6, and a personal computer 8. The image capture device 6 is disposed on top of the video display 4 to ensure that the local conferencee 10 has an unobstructed view of the information on the display 4. This necessarily produces a vertical offset between the image capture device 6 and the local conferencee 10 such that, when looking at the display 4 as at 12, the local conferencee 10 appears to be looking away from the image capture device 6 from the vantage of the remote conferencee. In order to establish face-to-face contact with the remote conferencee, the local conferencee 10 must look directly into the lens of the image capture device 6 as at 14. This disadvantageously restricts the local conferencee's 10 ability to view the information displayed on the display 4.
Although described above in the context of a video conferencing system, it is to be understood that this problem exists in every computer-based application where an operator wants to capture his or her own image. These applications may include, but are not necessarily limited to, video conferencing, video telephony, video messaging, video postcard, multimedia training, and multimedia authoring.
The present invention is directed at overcoming, or at least reducing the effects of, one or more of the problems set forth above.